• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.50-57
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• 2004

Selection of yeast strains, optimum conditions for alcohol fermentation, sterilization methods, and additives for improving wine quality were investigated to manufacture watermelon wine. Eight yeast strains exhibited significant alcohol fermentation, among which KWS 06 was selected for watermelon wine fermentation, because watermelon wine made by this strain showed the best overall acceptability in sensory evaluation. Sucrose was determined as the best saccharide for alcohol fermentation among sucrose, corn syrup, glucose, fructose, and lactose. Optimum concentration of soluble solid and $(NH_{4})_{2}HPO_{4}$ of nitrogen source were $24^{\circ}Brix and 0.2%, respectively. Addition of raspberries and omija increased wine flavor and alcohol production, respectively, with optimum alcohol production, taste, and color achieved with addition of 20 g/L raspberries and 10 g/L omija. Best sensory quality was obtained by addition of 0.04 % watermelon flavorant to the juice.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1280-1286
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• 2011

A quantitative, real-time PCR method was developed to enumerate Lactobacillus plantarum IWBT B 188 during the malolactic fermentation (MLF) in Grauburgunder wine. The qRT-PCR was strain-specific, as it was based on primers targeting a plasmid DNA sequence, or it was L. plantarum-specific, as it targeted a chromosomally located plantaricin gene sequence. Two 50 l wine fermentations were prepared. One was inoculated with 15 g/hl Saccharomyces cerevisiae, followed by L. plantarum IWBT B 188 at $3.6{\times}10^6$ CFU/ml, whereas the other was not inoculated (control). Viable cell counts were performed for up to 25 days on MRS agar, and the same cells were enumerated by qRT-PCR with both the plasmid or chromosomally encoded gene primers. The L. plantarum strain survived under the harsh conditions in the wine fermentation at levels above $10^5$/ml for approx. 10 days, after which cell numbers decreased to levels of $10^3$ CFU/ml at day 25, and to below the detection limit after day 25. In the control, no lactic acid bacteria could be detected throughout the fermentation, with the exception of two sampling points where ca. $1{\times}10^2$ CFU/ml was detected. The minimum detection level for quantitative PCR in this study was $1{\times}10^2$ to $1{\times}10^3$ CFU/ml. The qRT-PCR results determined generally overestimated the plate count results by about 1 log unit, probably as a result of the presence of DNA from dead cells. Overall, qRT-PCR appeared to be well suited for specifically enumerating Lactobacillus plantarum starter cultures in the MLF in wine.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.633-642
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• 2008

Several domestic new varieties of grapes were utilized for the fermentation of wines, including Cabernet Sauvignon, NY 21576, Canner, SV 18315, Agawan, and Black Bagal red wines, and Naples, Aligote, and Alicante white wines. The oBx values of the grapes ranged between 17 and $20^{\circ}Bx$. Soluble solid content was adjusted to $21^{\circ}Bx$ by adding sugar for all grapes and fermented at $20^{\circ}C$ for 2 weeks. Black Bagal and Cabernet Sauvignon were relatively slower than other grapes with regard to alcohol production rate. The L value of wine made from Agawan and NY 21576 were lower and darker than those of wines prepared from other grapes. Wine made from NY 21576 grapes had a polyphenol concentration of 1.40 mg/mL, which was higher than that of any other wine, whereas wines made from MBA and all white wines evidenced value of only 0.55 mg/mL and 0.15 mg/mL, respectively, after 2 weeks of fermentation. The sensory evaluations demonstrated that the quality of red wines made from NY 21576, Cabernet Sauvignon, Black Bagal, and that of white wines made from Naples grapes were favorable among the different grape variants.

• The Korean Journal of Food And Nutrition
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• v.23 no.3
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• pp.324-331
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• 2010

This study was designed to test the effects of enzyme treatments on the extraction of total phenolic compounds and on color characteristics in wines from domestic MBA(Muscat Bailey A) grapes. The total phenolic compound content of the MBA grape wine was $1,352.8{\pm}37.8\;mg/{\ell}$ at 10 days of fermentation. Furthermore, MBA wines treated with 2%(v/v) of Pectinex and Viscozyme had 14.5%(p<0.05) and 3.8% increase, respectively, in total phenolic compound content by 10 days of fermentation. Pectinex treatment was more effective for phenolic levels than Viscozyme treatment. The L, a and b values of the MBA grape wine were 7.4, 9.2 and -1.2, respectively, by 10 days of fermentation. The values in case of Pectinex enzyme treatment were 7.0, 10.6 and -0.8, respectively, and these values were significantly different according to Pectinex treatment(p<0.05). But the values in case of Viscozyme enzyme treatment were 7.2, 9.8 and -1.1, respectively, and these values were not different according to Viscozyme treatment. The hue and color intensity values of the MBA grape wine were 0.492 and 0.785, respectively, by 10 days of fermentation. The values in case of Pectinex enzyme treatment were 0.460 and 0.881, respectively. And as a result of the Pectinex treatment, the hue value of wine was decreased and color intensity was increased slightly(p<0.05). But the values in case of Viscozyme enzyme treatment were 0.482 and 0.805, respectively, and these values were not different according to the Viscozyme treatment.

• Food Science and Preservation
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• v.22 no.5
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• pp.768-777
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• 2015

Persimmon contains high levels of vitamins and phenolic compounds, as well as soluble solids, necessary for the fermentation of persimmon wine. Co-fermentation of persimmon wine was carried out using a mixed culture of Pichia anomala JK04, a Korean indigenous yeast that improves wine quality and flavor, and Saccharomyces cerevisiae Fermivin, an industrial wine yeast, in the following ratios: 9:1 (v/v), 5:5 (v/v), 1:9 (v/v) and 0:10 (v/v). During fermentation, the alcohol contents increased more slowly in samples of mixed culture than in samples of the single culture of S. cerevisiae Fermivin. The alcohol contents of all samples reached 12~13% (v/v) after 15 days. All samples of the mixed culture showed greater variety in flavor and taste than S. cerevisiae Fermivin only. In the sensory evaluation, mixed culture samples had higher scores in terms of flavor and overall preference than the single culture samples. Therefore, P. anomala JK04 is thought to improve the wine flavor of Korean domestic persimmon wine.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.761-767
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• 2022

EHT1 and EEB1 are the key Saccharomyces cerevisiae genes involved in the synthesis of ethyl esters during wine fermentation. We constructed single (Δeht1, Δeeb1) and double (Δeht1Δeeb1) heterogenous mutant strains of the industrial diploid wine yeast EC1118 by disrupting one allele of EHT1 and/or EEB1. In addition, the aromatic profile of wine produced during fermentation of simulated grape juice by these mutant strains was also analyzed. The expression levels of EHT1 and/or EEB1 in the relevant mutants were less than 50% of the wild-type strain when grown in YPD medium and simulated grape juice medium. Compared to the wild-type strain, all mutants produced lower amounts of ethyl esters in the fermented grape juice and also resulted in distinct ethyl ester profiles. ATF2, a gene involved in acetate ester synthesis, was expressed at higher levels in the EEB1 downregulation mutants compared to the wild-type and Δeht1 strains during fermentation, which was consistent with the content of acetate esters. In addition, the production of higher alcohols was also markedly affected by the decrease in EEB1 levels. Compared to EHT1, EEB1 downregulation had a greater impact on the production of acetate esters and higher alcohols, suggesting that controlling EEB1 expression could be an effective means to regulate the content of these aromatic metabolites in wine. Taken together, the synthesis of ethyl esters can be decreased by deleting one allele of EHT1 and EEB1 in the diploid EC1118 strain, which may modify the ester profile of wine more subtly compared to the complete deletion of target genes.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.319-326
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• 2001

Red wines were prepared with Campbell Early harvested at Youngdong, Chungbuk Province in 1999 of which average sugar content and total acidity(tartaric acid %) were $12^{\circ}Brix$ and 0.7%, respectively. In order to investigate the effect of addition of various sugars on the quality of red wine, sucrose, xylitol, glucose, corn syrup, high fructose corn syrup(HFCS) and isomaltooligosaccharide(IMO) were added to musts to have $21^{\circ}Brix$ of sugar content. Fermentation of red wine in which glucose was added was faster than any other sugars with the final ethanol content of 12%(v/v). Wines to which sucrose and HFCS were added showed similar fermentation rates to glucose added one but alcohol contents were 10.3%(v/v) and 11.2%(v/v), respectively. Alcohol contents of wines made with xylitol, corn syrup and IMO was relatively low to about 7% (v/v) after fermentation. The pH values of wines were almost unchanged in all treatments during fermentation and the total acidities of wines were decreased from 0.7% to lower than 0.3%. The colors of wines were changed to redder and darker during fermentation. In sensory evaluation xylitol added wine showed the best preference and kept xylitol unfermented in it.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.4
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• pp.582-588
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• 2010

Production of vinegar by fermentation using Rubus crataegifolius (Korean raspberry) and Rosa rugosa Thunb (Haedanghwa) were investigated. At the first step, ethanol fermentation performed for 12 days on Haedanghwa wine containing $17.6^{\circ}Brix$ sugar concentration, 6.2% ethanol concentration, and pH 2.9, and on Korean raspberry-Haedanghwa wine containing $7.0^{\circ}Brix$ sugar concentration, 11.4% ethanol concentration, and pH 3.4. In the second step, after supplementation of 1% acetic acid to Haedanghwa wine and Korean raspberry-Haedanghwa wine which adjusted their ethanol concentration to 6%, aerotropic acetic acid fermentation was carried out using Acetobacter aceti at $30^{\circ}C$ and 200 rpm for a period of 12 days. Korean raspberry-Haedanghwa vinegar contained a 3.7% concentration of acetic acid. Total phenolic compounds and color in Korean raspberry-vinegar was higher than that in Rosa rugosa Thunb vinegar. This result demonstrates that use of Korean raspberry and Haedangwha mixture for vinegar fermentation improves the color and taste of the final product.

• Journal of Microbiology and Biotechnology
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• v.21 no.5
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• pp.519-524
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• 2011

The correlation between alcoholic fermentation rate, measured as carbon dioxide ($CO_2$) evolution, and the rate of hydrogen sulfide ($H_2S$) formation during wine production was investigated. Both rates and the resulting concentration peaks in fermentor headspace $H_2S$ were directly impacted by yeast assimilable nitrogenous compounds in the grape juice. A series of model fermentations was conducted in temperature-controlled and stirred fermentors using a complex model juice with defined concentrations of ammonium ions and/or amino acids. The fermentation rate was measured indirectly by noting the weight loss of the fermentor; $H_2S$ was quantitatively trapped in realtime using a pre-calibrated $H_2S$ detection tube which was inserted into a fermentor gas relief port. Evolution rates for $CO_2$ and $H_2S$ as well as the relative ratios between them were calculated. These fermentations confirmed that total sulfide formation was strongly yeast strain-dependent, and high concentrations of yeast assimilable nitrogen did not necessarily protect against elevated $H_2S$ formation. High initial concentrations of ammonium ions via addition of diammonium phosphate (DAP) caused a higher evolution of $H_2S$ when compared with a non-supplemented but nondeficient juice. It was observed that the excess availability of a certain yeast assimilable amino acid, arginine, could result in a more sustained $CO_2$ production rate throughout the wine fermentation. The contribution of yeast assimilable amino acids from conventional commercial yeast foods to lowering of the $H_2S$ formation was marginal.

• Food Science and Preservation
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• v.17 no.1
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• pp.72-78
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• 2010

To develop a low-ethanol strawberry wine, the use of pectinase to improve the extraction yield of strawberry juice was investigated, and changes in physicochemical characteristics during ethanolic fermentation were assessed. The juice yield from strawberry fruit increased by 18.9% after Viscozyme L treatment (1,000 ppm, 30 min), compared with a control group, a greater increase than seen with other pectinases (17.5-18.7%). No significant quality differences were observed between control juice and juice prepared with enzyme treatment, indicating that neither physicochemical characteristics nor ethanol content during fermentation were affected by pectinase treatment. The major pigments of strawberry juice were cyanidin-3-glucoside and pelargonidin-3-glucoside, both of which are anthocyanins. The pigment level after enzyme treatment was slightly lower than that of the control group, at all fermentation times. We consider that the economics of strawberry wine manufacture may be increased by use of pectinase because juice level was increased, but no change in ethanol content or physicochemical characteristics was apparent.